Removal of Small-Sized Space Debris by Laser-Ablative Momentum Generation

Kurzfassung

Laser-based space debris removal concepts have been around for decades now. Nevertheless, practical implementation is still connected to great technological risks. Most of the concepts plan to utilize the laser ablative process at the target. To investigate this common aspect in detail and to reduce the risk of misleadingly extrapolating parameters, we now experimentally investigated the generation of impulse under realistic conditions as to be expected in a real space scenario. A Nd:YAG based, 10 ns pulsed MOPA laser system providing a pulse energy of 80 J was weakly focused to a diameter of 3 cm onto debris-like targets with different sizes, shapes and materials. The target masses ranged between 1 g to 3 g, indeed representing dangerous objects, and were in free fall within a vacuum during single pulse irradiation. High speed 3D-tracking was applied to deduce the kinetic properties induced by the ablation process. Finally, the data was compared to raytracing based simulation results. Differences between materials and mechanical dynamics are discussed. In simulations we explore operational safety issues as well as both potential and limitations of laser-ablative momentum generation, in particular with respect to the accumulation of residual heat from the ablation process. For this purpose, we use Monte Carlo simulations in order to analyze how restrictions in laser pointing accuracy as well as random target orientation affect the predictability of laser-ablative momentum generation. Moreover, pulse number restrictions are discussed in order to avoid target melting and its compactification.